


life within and without walls

by snakelesbians



Category: Kamen Rider Build
Genre: Ambiguous/Open Ending, Before During and After Canon, Getting Together, Other, POV Multiple, updated to fix my incorrect posting - thanks to the aussie government for our internet
Language: English
Status: Completed
Published: 2020-07-04
Updated: 2020-07-04
Packaged: 2021-03-04 00:41:00
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 2
Words: 2,538
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/24924799
Author URL: https://archiveofourown.org/users/snakelesbians/pseuds/snakelesbians
Summary: A look into the feelings of Kasumi and Sento about their time with Banjou Ryuga
Relationships: Banjou Ryuuga/Kiryuu Sento, Banjou Ryuuga/Kiryuu Sento/Ogura Kasumi, Banjou Ryuuga/Ogura Kasumi
Kudos: 5
Collections: Toku Poly Ficathon 2020





	1. Kasumi

**Author's Note:**

  * For [magicites](https://archiveofourown.org/users/magicites/gifts).



> I hope this is an enjoyable read even if it got a bit away from me.

When Kasumi became sick she noticed immediately the effect that it was having and would continue to have upon her fiance. He became more stressed and his fights became more vicious as he took out his anger over her situation on other people. Together they struggled to earn money to pay for her treatments, treatments that oftentimes produced minimal to no results in improving her condition. As time dragged on and her situation worsened she worried about how Ryuga would manage when she inevitably passed on, a worry that only intensified when he was banned from fighting due to the fixing that he had participated in to fund her last ditch treatments. When Kasumi realised that the tip off she had received that resulted in her mentioning Katsuragi Takumi to Ryuga was a set up, she was devestated knowing that she had unwittingly lead to her fiancée being framed for murder, a muder that she was positive that he would never commit of his own volition. 

The time that she spent as a monster was overwhelmingly filled up by pain and confusion, the presence of bright colours and blood, the flashing lights of the kamen rider who had arrived with Ryuga. Her first clear emotion once she had been separated from the monster that her body had become was relief, the relief that she was no longer having to fight her beloved fiancée, the man who was holding her in his arms tenderly, the hint of tears in the corner of his eyes. As she faded away she hoped that the kamen rider would protect and care for Ryuga now that she no longer could, and that one day Ryuga could be happy and safe even without her around. 

* * *

Thrumming

Sparks of Power

The heat of battle  


  
Otherworldly Power

Ryuga’s Power

….Ryuga

* * *

The sensation of her very being, the essence that made up what remained of Kasumi and was now contained within the dragon full bottle crawling out from the centre of the belt and becoming the armour that protects her most precious person, gave her what could almost be satisfaction, an almost feeling that manifested as an extra jolt of electricity covering the surface of the Rider that would eventually be named Cross-z. 

As they fought together Kasumi’s consciousness faded more and more, going from concrete almost human feelings and light sensation to the occasional wisps of feelings mostly fed through the bottle from Ryuga, her consciousness never made it to the advent of the new world.

* * *

Ogura Kasumi led a content and pleasing life, her fiancée was a successful and popular MMA fighter, she managed him and a number of other fighters, all women. They earnt enough money to be comfortable and enjoy themselves and together they strove to improve themselves and help others in their lives whenever possible. The advent of Kasumi regaining her memories of the old world, the one in which the sky wall towered over them, changed many things for the couple. 

When she regained her memories Kasumi was overtaken by double vision as she looked upon her fiancée with his dark hair and her vision flashed between the man standing before her and the man he was in the other world, the man with the bright hair and the slightly broken smile, the man whose arms she died in, the man who used the power of the essence she left behind to save many, the man who was saved and protected by the kamen rider in the red and blue, the man who was in front of her but was now gone. It didn’t take her long to realise that he had no memories of the other world, that the man she loved was only one of the two versions that she had known, and while she was glad that he was alive and they were together and healthy, she was saddened by the absence of his memories of the other times they had spent together, the struggles they had been through together and the love that they had shared, different but no less potent than the love they had in this new world free of much of the strife that had plagued them before. Kasumi strived to make the most of what she now knew was her second chance at a happy life with the man that she loved.

* * *

The sky was cracking, people ran past Kasumi as she ran forwards heading towards the stadium in which her partner had been in the middle of a match, the first match where he was defending champion rather than a challenger to the title. A monster had crashed through the roof in the time prior to her arriving at the venue and the area was a mess of smoke and rubble, the sky above reminiscent of magma tearing up the earth. As she entered what remained of the building Kasumi could hear the sounds of fighting within and while turning the corner she could see that the being fighting the monster she had seen before the connection dropped out was a person covered in purple armour, energy sparking from their hands. Upon spotting her they yelled and gestured for her to get away, directions she gladly followed continuing to search for Ryuga. 

After many stressful minutes she found him in one of the once halls, rebar lanced through his chest cavity from the ceiling partially collapsing around him, she rushed towards him but was intercepted by a familiar red and blue figure crashing through the rubble in front of her. As she stood there in shock he herded through a group of people decked out for the match and clearly distressed by the sudden attack that had left them trapped in the stadium. The Kamen Rider jolted in shock when he saw her, clearly not having noticed her in the initial rush to free the trapped civilians. 

"You should escape before the building becomes even more destabilised, it's not safe inside." The Rider appeared to be on the verge of attempting to shoot her away from the scene.

"I can't leave while my fiancée is trapped and injured!" She yelled back at him pointing behind the rider to where Ryuga still lay trapped.

At her words and gesture the Rider quickly turned around to see the man in question still stuck and bleeding from his wounds that were becoming more obscured by the second. 

The pair stood in front of the injured fighter concern evident in their body language but before either of them could speak there was another crash and a Rider with a body radiating heat ran into the hallway looking around wildly before running towards the sole people in the area. 

"Sento! I've been looking for you! Rogue destroyed the monster but the authorities are on the way we need to get out of here!!" He yelled gesturing with his hands flailing and snacking into the wall nearby causing it to crumble further. Before the newly dubbed Sento or Kasumi could respond he registered the presence of the third person in their area. 

"ME?!"

His armour melted away to reveal the person that Kasumi had been thinking off for months now, the other world's Ryuga. He reached out stopping any possible response the other two could have by touching the face of the other version of him causing their vision to white out. 

When their vision returned in front of Kasumi and Sento stood only one man, Banjou Ryuga. The only and only Kamen Rider Cross-Z. The strongest man either of them knew. The man they both loved. 


	2. Sento

When Sento first met Banjou Ryuga he was highly unimpressed, not only was the supposed murderer loud and angry, he was a genuine imbecile. Regardless of these facts, sento had chosen to help him simply because the loudmouth was his Best Match, potentially his only chance at finding out about the batman and what had happened to him, maybe even why he had no memories before meeting the owner. On top of all of that he did truly believe that the fugitive man was innocent of his crimes, in spite of his better interests he believed in and wanted to help prison escapee even though it had already made his life harder than it previously was. Sento just hoped that sharing a sleeping area with a third person would not be too stressful.

* * *

The first few weeks of sharing the basement with Banjou we excruciating, the man was just as obnoxious and loud as Sento feared he would continue to be, he constantly interfered with Sento’s experiments and fought to take up the space that Sento had made for himself, and on top of these things he had the gall to show Sento up by figuring out the secret of the Full Bottles and their Best Matches. That idiotic musclehead had shown up him! The gorgeous and unparalleled genius scientist, in his own area of knowledge! Sento was infuriated, Misora and Owner’s obvious amusement over the situation did not help in the slightest.

* * *

Their slowly growing piece was broken with the death of Ogura Kasumi. When Banjou’s fiancée died Sento didn't know how to help, his lack of memories left him in a state where he could not relate to his loss and his lack of worldly knowledge made empathising with him difficult. His only option was to try and comfort him physically, coercing the man that he was still resisting calling a friend into accepting a hug, a hug that led to them falling asleep together while Banjou attempted to keep his tears discreet and out of Sento’s sight.

* * *

Giving the dragon to Banjou was something that Sento did reluctantly, giving a powerful potential weapon to someone that had proven to Sento that they had the potential to instigate violence of a whim and with motives that Sento still did not understand. When Banjou overcame his limits and defeated a smash with his bare hands and nothing else but the Dragon Full Bottle, transforming into Build’s DragonLock form felt like a major step forward in their relationship, using the power that Banjou had claimed for himself to fight for them both gave him a warm feeling that he was not sure how to interpret for himself.

Banjou transforming into a Kamen Rider himself marked the next big change in their relationship and took Sento from thinking of them as friends to thinking of them as partners, a thing that he would never admit directly to the man himself. Once he had created a second belt for Banjou’s use it became somewhat enjoyable to fight alongside the other, having another person to support him directly in the fight against faust became even more essential once he had discovered the true identity of Bloodstalk and himself, Banjou and Misora were forced to abandon Nascita. 

* * *

Sento was NOT in love with Banjou Ryuga, his partner, the one he relied on, the person he trusted the most in the world he WASN’T in love with him.

Being accidentally fused with Banjou challenged these personal assertions of Sento’s. The feeling of being so close to his partner filled Sento with a sense of completion and warmth that he had never felt before, a feeling he wasn't sure that even Katsuragi Takumi had felt in his time. It felt so much more fulfilling to defeat their enemies as one entity than as individual Riders, a fulfillment that he was terrified that Banjou might guess at and correctly understand the reason behind Sento’s fulfillment. 

* * *

After using their combined power to combine the worlds and save them all Sento woke up alone. Finding Banjou walking with his no longer dead fiancée, his hair dark and his smile bright, crushed Sento. He wanted to be happy that Banjou was but he couldn’t help but feel that something had been taken away from him and left him bereft. 

Being found by HIS Banjou reinvigorated Sento, the knowledge that the musclehead who had fought beside him, the idiot that had been with him through the tough times in the old world, the clown that he loved, had returned to him filled him with joy that he had never before felt. It felt so right to walk away from that other version of Banjou with the one that he knew and cared for beside him, it felt so good to tease him just like he had when they first met and he never knew how much he would come to understand and care for the man he had initially thought was a murderer. It was nerve wracking to slip his hand into Banjou’s and pleasing to have the man squeeze his hand in response. 

* * *

The sky was lanced through with cracks above the group of Kamen Riders situated outside the large stadium in which many civilians were located, Rouge was fighting one-on-one with the monster responsible for the situation as the other three riders ran inside the building as it began to collapse, splitting up to cover as much ground as possible and to save everyone inside. It had been many minutes and Sento continued to find people trapped inside the building and attempting to escape, he cleared the rubble ceaselessly to assist them in their attempts. Pushing aside rubble he pushed into a corridor, leading the civilians with him though and towards safety, he looked around to survey the area and was surprised to see a familiar face looking back at him, Ogura Kasumi. 

"You should escape before the building becomes even more destabilised, it's not safe inside." Sento told her, alarmed that she was present at the scene of destruction.

"I can't leave while my fiancée is trapped and injured!" Kasumi yelled back at him and pointed to a space behind Sento.

He turned to see a scene that shocked him to his core, the new world’s Banjou Ryuga struck through with rebar and bleeding out.

The pair moved in front of the injured man and looked towards him as Sento thought on what he could do to free the man without furthering his injuries. Before he could put forward any suggestions to fix the situation his idiotic boyfriend barged his was into the corridor in which they stood.

"Sento! I've been looking for you! Rogue destroyed the monster but the authorities are on the way we need to get out of here!!" His Banjou yelled, swinging his arms around wildly, he appeared to be about to continue his building rant before he saw their situation and cut himself off. "ME?!"

Banjou immediately dissolved his transformation and reached out towards his other self, moving too fast for Sento or Kasumi to say anything or stop him. His hand landed on the face of his other self as Sento opened his mouth to tell him off about the potential ramifications of his actions. Ramifications that made themselves immediately clear as the world disappeared in a bright light. A light that when cleared showed the rebar once lanced through the dark hair Banjou lying on the ground and standing in front of it one singular Banjou Ryuga, Sento’s boyfriend had appeared to merge with Kasumi Ogura’s fiancée to create a singular person.

**Author's Note:**

> fixed up all the issues and i am considering a sequel focusing on Ryuga before-during-after this if anyone would be interested in that. sorry about my messed up initial posting and i hope this was fun to read!


End file.
